Project Summary Differences in cognitive information processing of threat information have been linked with almost every major psychiatric illness, from anxiety to psychosis to PTSD. And yet, objective, performance-based measures of such threat sensitivity tend to be (1) unreliable, (2) difficult to scale, and (3) designed for assessing differences in phenotypic traits rather than characteristics that vary over time. Self-reported experiences linked with threat processing (e.g. anxiety, hypervigilance, fear), on the other hand, tend to fluctuate over minutes, hours, and days within individuals. The lack of brief, sensitive, reliable, and repeatable measures of threat sensitivity thus represents a major gap in our ability to understand how threat sensitivity is related to mental health, between individuals and over time. The overall goal of the proposed project is to develop and validate a battery of optimized and generalizable measures for assessing between and within-person differences in threat sensitivity, for use in high throughput or high frequency assessment designs. The proposed work is organized around three specific aims. Aim 1 is to identify and optimize a set of 5 reliable candidate measures, based on an initial set of 25. We will select and develop measures based on an iterative test development approach, using high-throughput assessment in N = 75,000 participants to identify parameters, stimuli, and administration characteristics that allow us to meet pre-specified psychometric and validation benchmarks across device types (see Research Strategy). Measures that achieve these benchmarks will then be carried over to two large-scale EMA validation studies: (1) a sample recruited from an acute psychiatric care setting at McLean Hospital (Aim 2, N = 200) and (2) a diverse Bronx-biased community sample (Aim 3, N = 400). Successful completion of this project will yield a set of high-quality measures that are validated for research using both high throughput and high frequency assessment study designs (e.g. EMA), particularly research that seeks to characterize the temporal dynamics of threat processing or state-related differences in cognition and symptoms. The proposed research is significant because it will (1) address a critical gap in our ability to objectively measure cognitive information processing of threat in field test settings, and (2) provide robust tools for tracking changes in threat sensitivity over time. The proposed research is innovative in that it (a) employs an iterative test development approach that will allow us to rapidly select and optimize potential test candidates, administered in naturalistic environments, and (b) allows us to capture both between and within-subject variability as potential avenues for identifying mechanisms that contribute to mental disorders Our team is uniquely positioned to accomplish these aims, given our expertise in developing and evaluating mobile cognitive assessments, psychometrics, fear and threat information processing, and infrastructure for disseminating cognitive measures in large cohorts and nationally.